Diazaquinomicyn A is a natural 1,8-diazaanthraquinone found during the routine study of secondary metabolites from bacteria. [S. Omura, et. al., J. Antibiotics, 35, 1425 (1982); and S. Omura et. al., Tetrahedron Letters, 24, 3643 (1963)]. It exhibits good activity against Gram positive bacteria, due to its capacity to inhibit the thymidylate synthetase [S. Omura, et. al., J. Antibiotics, 38, 1016 (2985); and M. Murata et. al T. Miyasaka, H. Tanaka, S. Omura, J. Antibiotics, 38, 1025 (1985)]. However, Diazaquinomycine A is inactive as an antitumoral agent.
It has now been found, in accordance with the present invention, that certain azaanthracene-triones, as hereinafter defined, possess antitumoral activity.